Exothermic process with porous means to control reaction rate and exothermic heat

ABSTRACT

An exothermic process for forming a product which may be in a liquid phase is disclosed wherein a first reactant, preferably a liquid reactant, is directly fed into a reaction zone containing mixing elements and which comprises a first compartment of a reactor. A second reactant, which is maintained at a higher pressure, is fed into a second compartment of the reactor separated from the first compartment by a porous wall. The second reactant passes through this porous wall into the reaction zone to react with the first reactant. The process thereby controls rates of the reactions and the exothermic heats generated by the reactions. Pulsatile flow in one or both reaction compartments improves mixing. An evaporator for a portion of the product improves product quality and permits higher reaction temperatures in the reactor.

BACKGROUND OF THE INVENTION

Related Applications

This application is a continuation-in-part application of U.S. Ser. No.024,989, filed Mar. 2, 1993 now abandoned. This prior application isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to a controlled exothermic process for reactingtogether two or more reactants. One reactant-is fed at a first pressureinto a first zone in a reactor containing mixing means and a secondreactant is fed at a higher pressure into a second zone in the reactor.The second zone is separated from the first zone by a porous barrierwall through which the second reactant passes. In this way, a controlledflow of second reactant into the first reactor zone and control of theexothermic reaction are achieved.

DESCRIPTION OF THE RELATED ART

Exothermic processes for forming a reaction product from at least tworeactants wherein the desired product is a liquid phase or high densitysupercritical phase at the reaction conditions are typically carried outin a thin film reactor such as a falling film reactor. For example,Ashina et al. in U.S. Pat. No. 3,918,917 describes a multi-tubethin-film type reaction apparatus for the reaction of an organiccompound and gaseous sulfur trioxide comprising a reaction tube providedwith gas and liquid feeding tubes at the upper end of the reaction tube.

It is also known to carry out such reactions radially by passingreactants into a cylindrical reactor through the outer walls of thecylinder and to collect the resultant product through an aperturedcentral tube in the cylindrical reactor.

For example, Newson in U.S. Pat. No. 3,844,936 discloses a radialdesulfurization process and apparatus wherein both oil and hydrogen areperipherally introduced through sidewall nozzles into a cylindricalshell packed with catalyst. A tube having apertures therein passesthrough the center of the cylindrical shell, and both the oil and thehydrogen gas, passing through the catalyst in the outer shell, enter thecentral tube through the apertures and leave the apparatus.

De Rosset in U.S. Pat. No. 3,375,288 discloses a process and apparatusfor dehydrogenation of hydrocarbons wherein a hydrocarbon feedstock tobe dehydrogenated is fed into a reaction zone containing a particulatedehydrogenation catalyst. The reaction mixture, while undergoingdehydrogenation, is also contacted with one side of a tubular thinpermeable membrane, such as a silver tube which has a high permeabilityto oxygen. Oxygen at a higher partial pressure is maintained on theopposite surface of the tube and diffuses through the tube to react withthe hydrogen being liberated in the dehydrogenation process.

The use of permeable membrane catalysts, particularly the use ofpalladium alloy catalyst membranes, have been the subject of muchinvestigation. Mischenko et al. in U.S. Pat. No. 4,179,470 describe aprocess for producing aniline by catalytic hydrogenation of nitrobenzenewhich comprises using a membrane catalyst which is essentially an alloyof palladium and ruthenium. The hydrogenation is carried out by feedingnitrobenzene on one side of the membrane catalyst and hydrogen on theother side. The hydrogen reactant diffuses through the membranecatalyst, which is shaped as a foil, into the hydrogenation chambercontaining the nitrobenzene reactant.

Gryaznov et al., in an article entitled "Selectivity in Catalysis byHydrogen-porous Membranes", published in Discussions of the FaradaySociety, No. 72 (1982) at pages 73-78, disclose the use ofhydrogen-porous membrane catalysts through which hydrogen may pass,either during a dehydrogenation reaction to raise the reaction rateand/or suppress side reactions; or during a hydrogenation reaction toindependently control to some extent the surface concentration ofhydrogen and to obtain incompletely hydrogenated products which arethermodynamically unstable in the presence of hydrogen.

V. M. Gryaznov, in an article entitled "Hydrogen Permeable PalladiumMembrane Catalysts", published in Platinum Metals Review, 1986, 30, (2)at pages 68-72, describes the catalytic properties of selected palladiumbinary alloy membranes, which are only permeable to hydrogen, duringhydrogenation and dehydrogenation reactions.

Armor, in a review entitled "Catalysis with Permselective InorganicMembranes", published in Applied Catalysis, 49(1989) at pages 1-25,discusses the work of others with various catalytic membranes, includinghydrogen-permeable palladium membranes, ceramic-supported palladiummembrane catalysts, ceramic membranes permeable to oxygen, porouspolymer resins used as membranes catalysts, and alumina membranecatalysts.

K. Omata, et al., in Applied Catalysis, Vol. 52, L1-L4 (1989) disclosethe oxidative coupling of methane using a membrane reactor. The catalystis on the membrane or barrier, and the reactor has no mixing elements.

W. M. Haunschild in U.S. Pat. No. 4,624,748 discloses a catalyst systemfor use in a distillation column reaction. The entire reaction mixturepasses through the permeable material. These ether-forming reactionsoccur at low temperatures up to about 100° C. Higher temperaturesapparently would destroy the membrane.

All patent applications, patents, articles, references, standards andthe like cited herein are incorporated herein by reference in theirentirety.

What is needed is a process that makes it possible to control the rateof an exothermic chemical reaction by controlling the rate of contact ofthe one or more reactants. The present invention accomplishes theseobjectives of controlling exothermic reaction rate by using a porousbarrier through which one or more of the reactants is introduced to thezone containing the other reactant(s), and contacting them using mixingelements.

SUMMARY OF THE INVENTION

The present invention comprises an exothermic process for forming aproduct which may be in a liquid phase wherein a first reactant, orcombination of first reactants, is directly fed into a reaction zonecontaining mixing elements and a second reactant or a combination ofsecond reactants, which is maintained at a higher pressure, istransported through a porous barrier into the reaction zone to reactwith the first reactant. Preferably, the first reactant is a liquid andthe second reactant is also a liquid. Control of both the reaction rateand the accompanying generation of exothermic heat are made possible bythe process.

In one embodiment, the present invention relates to an improved processfor forming a product by reaction of one or more first reactants and oneor more second reactants which comprises:

(a) feeding into a first reactor zone one or more first reactants at afirst pressure;

(b) feeding one or more of the second reactants at a second pressurehigher than the first pressure into a second reactor zone separated fromthe first reactor zone by a porous wall capable of being penetrated bythe second reactant; and

(c) maintaining the pressure within the second reaction zone at alllocations of the porous wall higher than the pressure in the firstreaction zone at corresponding locations of the porous wall, to therebyinhibit any flow through the porous wall from the first reaction zone tothe second reaction zone;

whereby one or more second reactants will pass through the porous wallto contact one or more first reactants in the first reactor zone andform the product.

In another embodiment, the present invention relates to an improvedprocess for forming a product by reaction of one or more first reactantsand one or more second reactants which comprises:

(a) feeding into a first reactor zone containing mixing elements thereinone or more first reactants at a first pressure;

(b) feeding one or more second reactants at a second pressure higherthan the first pressure into a second reactor zone separated from thefirst reactor zone by a porous wall capable of being penetrated by theone or more second reactants; and

(c) maintaining the pressure within the second reaction zone at alllocations of the porous wall higher than the pressure in the firstreaction zone at corresponding locations of the porous wall, to therebyinhibit any flow through the porous wall from the first reaction zone tothe second reaction zone;

whereby one or more second reactants will pass through the porous wallto contact one or more first reactants in the first reactor zone andform the product.

In another embodiment, the present invention relates to an improvedexothermic process for forming a product by reaction of one or morefirst liquid reactants with one or more second liquid reactants whichcomprises:

(a) feeding one or more first liquid reactants at a first pressurethrough a first reactor zone having mixing elements therein;

(b) feeding one or more second liquid reactants at a second pressurehigher than the first pressure into a second reactor zone separated fromthe first reactor zone by a porous wall capable of being penetrated byone or more second liquid reactants; and

(c) maintaining the pressure within the second reaction zone at alllocations of the porous wall higher than the pressure in the firstreaction zone at corresponding locations of the porous wall, to therebyinhibit any flow through the porous wall from the first reaction zone tothe second reaction zone;

whereby one or more second liquid reactants will pass through the porouswall to contact one or more first liquid reactants in the first reactorzone and form the product.

In yet another embodiment, the present invention relates to an improvedexothermic process for forming a product by reaction of one or moreliquid first reactants with one or more second reactants, at least oneof which is gaseous at ambient conditions, which comprises:

(a) feeding one or more liquid first reactants at a first pressurethrough a first reactor zone having mixing elements therein;

(b) feeding one or more second reactants, at least one of which isgaseous at ambient conditions, at a second pressure higher than thefirst pressure into a second reactor zone separated from the firstreactor zone by a porous wall capable of being penetrated by the one ormore second reactants; and

(c) maintaining the pressure within the second reaction zone at alllocations of the porous wall higher than the pressure in the firstreaction zone at corresponding locations of the porous wall, to therebyinhibit any flow through the porous wall from the first reaction zone tothe second reaction zone;

whereby the one or more second reactants passes through the porous wallto contact the one or more liquid first reactants in the first reactorzone and form the product.

In still another embodiment, the present invention relates to animproved exothermic process for forming a product by reaction of one ormore first reactants and one or more second reactants which comprises:

(a) feeding a first reactant at a first pressure through a first reactorzone containing mixing elements having at least one dimension equal tofrom about 1/2 to about 1/100 of the largest dimension of the firstreactor zone normal to the flow of the first reactant through the firstreactor zone;

(b) feeding a second reactant at a second pressure higher than the firstpressure into a second reactor zone separated from the first reactorzone by a porous wall capable of being penetrated by the secondreactant; and

(c) maintaining the pressure within the second reaction zone at alllocations of the porous wall higher than the pressure in the firstreaction zone at corresponding locations of the porous wall, to therebyinhibit any flow through the porous wall from the first reaction zone tothe second reaction zone;

whereby the second reactant passes through the porous wall to contactthe first reactant in the first reactor zone and form the product.

In still another embodiment, the present invention relates to animproved process for forming a product by reaction of a first liquidreactant with a second liquid reactant, which process comprises:

(a) feeding a first liquid reactant at a first pressure into a firstreactor zone containing particles having at least one dimension equal tofrom about 1/2 to about 1/100 of the largest dimension of the firstreactor zone normal to the flow of the liquid reactant through the firstreactor zone;

(b) feeding a second liquid reactant at a second pressure higher thanthe first pressure into a second reactor zone separated from the firstreactor zone by a porous wall capable of being penetrated by the secondliquid reactant; and

(c) maintaining the pressure within the second reaction zone at alllocations of the porous wall higher than the pressure in the firstreaction zone at corresponding locations of the porous wall, to therebyinhibit any flow through the porous wall from the first reaction zone tothe second reaction zone;

whereby the second liquid reactant passes through the porous wall tocontact the first liquid reactant in the first reactor zone and form theproduct.

In still another embodiment, the present invention relates to anapparatus for forming a product by reaction of one or more firstreactants with one or more second reactants, which apparatus comprises:

a reactor having one or more porous members therein dividing the reactorinto first and second reactor zones capable of being maintained atdifferent pressures; whereby the one or more first reactants in thereactor zone maintained at a higher pressure will pass through the oneor more porous members into the reactor zone maintained at a lowerpressure to contact one or more second reactants in the reactor zonemaintained at a lower pressure to form the product.

In still another embodiment, the present invention relates to any of theimproved processes described herein, wherein the process furtherincludes step (d), (e) and (f);

(d) conveying a portion of the reaction product of step (c) to anevaporator;

(e) separating volatile reactants or reaction products wherein the vaporpressure of the volatile reactants or reaction products is about 1 mm ofHg or higher at the temperature of the reaction in step (c); and

(f) optionally recycling all or a portion of all of the reaction productliquid now depleted of volatile reactants, reaction products or acombination thereof to the first reactor zone of step (a).

In another aspect, the rates of flow of the first reactant in thereactor are cyclic (pulsatile) from a maximum flow rate in one directionto a rate of about a 20% reverse flow of the maximum flow rate, andreturn to maximum flow rate.

In another aspect, the present invention also concerns a separation,e.g. a flash evaporation, of reactants or reaction products. Thisseparation improves the yield of the final product by reducing unwantedside reactions and reduces the formation of unwanted by-products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a partially cutaway verticalcross-sectional view illustrating the process of the invention beingcarried out in its simplest form.

FIG. 2 is a schematic representation of a vertical cross-sectionaldiagrammatic view of an apparatus suitable for use in carrying out theprocess of the invention.

FIG. 3 is a top view, in cross-section of the apparatus of FIG. 2 takenalong lines 3--3.

FIG. 4 is a schematic representation of a diagrammatic view of a seriesof stages of the apparatus generally illustrated in FIGS. 2 and 3.

FIG. 5 is a schematic representation of a graph depicting thetemperature and the conical reaction interface along the flow linewithin a tubular reactor.

FIG. 6 is a schematic representation of a diagrammatic illustration ofthe respective flows of Fluid A across the walls of the porous tube andFluid B through the tube.

FIG. 7A is a schematic representation of a cross-sectional viewillustrating how the porosity of a porous tube may be varied along itslength, with a shield over a portion of the porous tube.

FIG. 7B is a schematic representation of a cross-sectional viewillustrating how the porosity of a porous tube may be varied along itslength, with the shield shown in FIG. 7A moved to expose a furtherportion of the porous tube.

FIG. 8 is a schematic representation of the apparatus of the processadditionally having the separator (or evaporator) component and recyclemode.

DETAILED DESCRIPTION OF THE INVENTION

The present invention comprises an exothermic process for forming achemical product which may be in a liquid phase wherein a firstreactant, preferably a liquid reactant, is directly fed into a reactionzone containing mixing elements and which comprises a first compartmentof a reactor. A second reactant which may be either a liquid or gaseousreactant, and which is maintained at a higher pressure, is fed into asecond compartment of the reactor separated from the first compartmentby a porous wall or barrier. The second reactant passes through thisporous wall into the reaction zone containing mixing elements to reactwith the first reactant under controlled reaction conditions.

Basic Apparatus Useful in the Process

Referring now to FIG. 1, the concept of the process of the invention isillustrated in its simplest form. Within a reactor 2, a first reactorcompartment or zone 10 and a second reactor compartment or zone 20 areprovided, separated by a wall 30 having a porous portion 32 spaced fromboth the top and bottom of wall 30. Reactor zone 10 is packed withmixing elements 12, such as glass balls, preferably to a level aboveporous portion 32 of wall 30 so as to introduce mixing into the firstreactant stream 3 prior to transporting the second reactant into reactorzone 10.

A first reactant 3, which is preferably in a liquid phase, is fedthrough an entrance port 14 into first reactor zone 10 and a secondreactant 4, which is at a higher pressure than the pressure in firstreactor zone 10, is fed through entrance port 24 into second reactorzone 20. The second reactant 4 passes through porous wall portion 32into first reactor zone 10 where it reacts to form a product 5 which isremoved from first reactor zone 10 via exit port 16.

If desired, an exit port 26 is provided in second reactor compartment 20to permit the second reactant 4 to be circulated through second reactorcompartment 20, using a pump 22. As shown in FIG. 1, a heat exchanger 28may be optionally used to cool the circulating second reactant tothereby remove some of the exothermic heat being generated in reactor 2.

In a preferred mode, as shown in FIGS. 2 and 3, the reaction will becarried out in a multiple tube reactor 40, having one or more tubes 50housed in an outer shell 60 wherein a portion 52 of the wall of eachtube 50 will comprise porous material. Mixing elements 58 are placedwithin each tube 50 and a first reactant 3, which preferably is a liquidreactant, will be fed through an inlet port 42 in the top of reactor 40into an inlet plenum or manifold 44 connected to the open top end 54 ofeach tube 50. It will be noted that preferably mixing elements 58 arealso placed in inlet manifold 44 so that mixing flow conditions arealready created in the flow of first reactant in reactor 40 before thefirst reactant reaches tubes 50 and, therefore, before introduction ofthe second reactant 4 into the flow stream.

While 16 such tubes are illustrated in the reactor shown in FIGS. 2 and3, it will be understood that this is for illustrative purposes only anda commercial embodiment for practicing the process of the inventionwould utilize a large number of such tubes, e.g., as many as 50 or moresuch porous tubes.

The second reactant 4 is introduced through a first side port 62 inshell 60 of reactor 40 at a higher pressure than the first reactant tocirculate around all of the outside surfaces of tubes 50, including theporous portions 52 through which the second reactant is transported tocontact and react with the first reactant 3 within tubes 50.

The resultant product 5, as well as any unreacted reactants, may thenexit via open bottom ends 56 of each tube 50 into a second plenum ormanifold 46 which, it will be noted, also contains mixing elements 58.This positioning of mixing elements 58 along the entire length of eachtube 50, even beyond the porous portion of each tube 50 and into lowermanifold 46, is provided because there may be continued reaction betweenthe first reactant 3 and second reactant 4 even after the flow ofproduct 5 and reactants (3 and 4) passes beyond the porous portion ofeach tube 50. That is, the reaction zone may extend beyond the end ofthe porous portion of each tube 50.

The product 5, as well as any unreacted reactants, may leave reactor 40via exit port 48 at the bottom of reactor 40. An exit port 64 in shell60 of reactor 40 is also provided for the second reactant 4 to permitcirculation thereof, as well as possible additional use of the secondreactant as a coolant for reactor 40, as discussed above.

FIG. 5 is a schematic representation of a graph which depicts the changein temperature and the conical reaction interface 9A along the flow linewithin a porous tubular reactor, e.g. 52, having a reactor zone 9B.Within tube 52 is found a radial reaction zone 52A surrounded by aporous wall through which the second reactant 4 passes to react with thefirst reactant 3. The finishing zone 9C is not porous. The averagetemperatures are shown at various points in the tube. The graphillustrates that the temperature within the reactor gradually rises withno hot spots in the reactor, e.g. 40.

The porous barrier 52 may or may not have catalytic properties.Preferably the barrier or wall does not have catalytic properties.

Mixing Elements Used in Process

The presence of mixing elements 58 in the reaction zone provide a morethorough mixing of the reactants in the reaction zone to prevent orinhibit the occurrence of hot spots in the reaction zone which couldresult in creation or concentration of excessive heat which could damageeither reactants or product. The mixing elements preferably compriseinert materials such as glass or ceramic balls or other non-reactivepacking type material such as Raschig rings or beryl saddles. In someembodiments, the mixing elements are stationary. In other embodiments,the mixing elements are mobile within the reaction zone. In oneembodiment, the mixing elements do not have catalytic properties.

It is also within the scope of the invention, in another embodiment, forthe mixing elements to have catalytic properties as well, although itwill be appreciated that the main purpose of the mixing elements is tocreate multiple divisions and recombining of flow and thus provide formore thorough mixing of the reactants in the reaction zone in thereactor.

Thus, particulate catalysts conventionally utilized usually comprisefinely divided materials characterized by high surface areas and shortdiffusion distances to maximize the contact area between catalyst andreactants, at the expense of high pressure drops, resulting in lowerthroughput or the need to utilize more energy in passing the reactantsthrough such a catalyst bed.

In contrast, the mixing elements utilized in the process of theinvention are much larger in size than conventional catalysts so thatany negative impact on flow rates by the presence of such mixingelements will not be significant.

Preferably the mixing elements utilized in the process of the inventionhave a major dimension which ranges from about 1/100 to about 1/2,preferably from about 1/10 to about 1/3, of the largest dimension in theplane of the reaction zone normal to the flow of the reactants throughthe reaction zone. For example, when the mixing elements comprise ballsand the reaction zone comprises a cylindrical tube, the balls will havea diameter of from about 1/100 to about 1/2, preferably from about 1/10to about 1/3, of the diameter of the tube. Thus, if the reaction zonesare located within 2 cm I.D. tubes having porous tube walls, sphericalmixing elements utilized within the tubes will have diameters rangingfrom about 0.2 millimeters (mm) to 10 mm, and preferably will range fromabout 2 mm to 6.7 mm.

It should be further noted that while the presence of the mixingelements has been illustrated in the reaction zone, as well as in theregion just prior to the mixing zone, the mixing elements may also bereset in the conduits leading from the reactor to heat exchangers, andmay even be used in the heat exchanger tubes as well. This isparticularly true where the reaction zone, comprising the porous portionof a tube and the region of the tube beyond the porous region, is joinedto a heat exchanger forming an extension of the same tube, in which casethe entire tube is advantageously packed with such mixing elements.

The above configuration makes maximum uses of the tube volume. However,for many chemistries, the concern about the effects of possible leakagebetween the shell side fluids, the second reactant, and the coolingwater would preclude its use. For example, in the case of sulfonating anorganic compound, the second reactant 4 is SO₃, which would be separatedfrom the cooling water by a tube sheet. A pin hole would produce hotsulfuric acid which would soon enlarge the pin hole. In these cases,separate reactors and heat exchanges would be preferred.

Porous Material Used In the Process

The porous material initially separating the two reactants, and throughwhich the second reactant passes, will generally comprise a material ofcontrolled porosity, as opposed to a pore-free permeable membranethrough which transport is by diffusion, since such pore-free membranesprovide poor rate performance due to the low transport rate across themembrane. The porosity and pressure are adjusted to provide a minimumflow of the second reactant across the porous material, relative to theflow of the first reactant on the low pressure side of the porousmaterial (32 and/or 52), sufficient to permit reaction of the firstreactant on the low pressure side with the second reactant passingthrough the porous material.

However, the flow rate of the second reactant 4 across the porousmaterial, i.e., the porosity and pressure used, must be adjusted to notexceed that flow rate which will provide either reaction between thereactants or dissolving of the second reactant 4 into the first reactant3 on the low pressure side, i.e., a second phase (comprising the highpressure second reactant) should not be substantially formed in thereaction zone. By "substantially" is meant that not more than 10% of thehigh pressure second reactant passing through the porous material (32and/or 52) should form a second phase in the reaction zone.

Typically, the porous material will comprise a sintered metal. Theporous material may comprise a high porosity (coarse) material which hasbeen coated with a second material to control the pore size. Forexample, a porous stainless steel material may be coated with anon-reactive ceramic material such as zirconia. This, for example, couldbe done by coating a commercially produced sintered stainless steel tubewith finely divided zirconia or titania powder dispersed in a vehicle,allowing the vehicle to evaporate, and then firing the zirconia (ortitania)-coated tube at a temperature of 1000° C.

The coating of the commercially produced porous tube may be carried outby pumping a slurry or suspension of the coating materials, e.g.,zirconia or titania, through the walls of the porous tube, i.e., fromthe outside of the tube to the inside--or vice versa--until one achievedthe desired porosity. When the coating or changing of the porosity isdone by pumping a slurry from the outside to the inside of the poroustube, the need for heating to stabilize the porosity of the tube cansometimes be eliminated.

In one embodiment of such modification of an existing porosity of poroustube 52, it may be advantageous to provide a variable or profiledporosity in porous tube 52. Referring to the graph of FIG. 6, thepressure of Fluid B (aka 7) traveling inside porous tube 50 graduallydrops as Fluid B (7) flows within tube 52. This, in turn, means that thechange in pressure ΔP, across the porous wall of tube 52 increases alongthe tube in the direction of flow of Fluid B (7) (assuming that Fluid A(aka 6) has a constant pressure all along the length of tube 50 and/or52).

To compensate for this variable pressure drop across the wall of tube52, there should be a continually decreasing porosity in the porous wallof tube 52. One way of achieving this, as shown in FIGS. 7A and 7B, isto cover either the inside or outside surface of porous tube 52 with asleeve 400 which is slowly moved or retracted as the slurry 8 orsuspension of the coating materials, e.g., zirconia or titania, ispumped through the walls of the porous tube. By varying the amount ofmaterial pumped through the porous walls of the tube along the length ofthe tube in this manner, a profiled change in the porosity of the tubemay be achieved, with the portion of the tube 8A exposed the longest tothe coating materials having the lowest porosity and, therefore, beinglocated on the downstream end of the flow of Fluid B (or 7) through thetube.

The porosity of a porous metal substrate, such as a commerciallyavailable porous stainless steel tube, could also be modified by coatingthe porous tube with fine metal particles, and then sintering the coatedtube at a temperature sufficiently low to permit the particles to sinterto the porous substrate without fusing the porous substrate into anon-porous mass. Examples of metal powders which may be used, forexample, with a porous stainless steel tube include stainless steel,nickel, and chromium.

The porosity of the porous surface separating the first 3 and secondreactants 4 will be selected to provide a volumetric flow rate of secondreactant through the porous barrier which will result in the desiredrate of reaction between the reactants. If the exothermic heat given offduring the reaction is high, in accordance with the process of theinvention, the reaction may be slowed by lowering the flow of the secondreactant into the reaction zone. This may be accomplished, in accordancewith the present invention, by selecting a barrier material having alower porosity.

The viscosity of the reactant which is flowing through the porousbarrier, as well as the pressure difference between the two sides of theporous barrier and the area of the porous barrier, also must be takeninto account when attempting to adjust the volumetric flow of the secondreactant across the porous barrier to thereby exercise control of thegeneration of exothermic heat in the reaction zone. This viscosity, ifdesired, may be further controlled or adjusted by blending product withthe particular reactant before feeding the reactant into the reactionzone.

When these parameters are all taken into account, the porosity of aporous barrier of given area to a reactant of given viscosity at a givenpressure differential across the barrier to achieve a particularvolumetric flow rate may be expressed in the following equation:##EQU1## wherein: V=volumetric flow rate of the reactant going throughthe porous barrier, in cubic centimeters per second (cc/sec);

A=the outside area of the porous barrier in square centimeters (cm²);

μ=the viscosity of the second reactant passing through the porousbarrier in centipoise (cp);

ΔP=the change or difference in pressure from one side of the porousbarrier to the other side in pounds per square inch (psi); and

Q=the viscosity normalized permeance of the porous barrier material incm³ cp/cm² sec psi (where 1 pound per square inch (psi) is equal to6894.7 pascal).

It will, of course, be recognized that this "viscosity normalizedpermeance" of a given material will vary with the porosity of thematerial, the wall thickness of the porous barrier, and the wallmorphology, since the porosity may not be uniform. In accordance withthe invention, the Q value of the porous barrier initially used toseparate the first and second reactants should range from about 10⁻⁶ toabout 5×10⁻² om³ cp/cm² sec psi, preferably from about 10⁻⁶ to about10⁻⁴ cm⁻ cp/cm² sec psi, and most preferably from about 5×10⁻⁶ to about5×10⁻⁵ cm³ cp/cm² sec psi, to provide the desired initial separationwhile still permitting adequate permeance of the second reactant throughthe barrier to permit the reaction to proceed. The mean pore diameter ofthe pores in the barrier, depending upon its application, may generallyrange from between about 0.01 and 50 micrometer.

The temperature range maintained in the reactor 40 may range from thelowest temperature at which the particular second reactant 4 will stillpass through the porous material, and at which both reactants (3 and 4)will be in either the gaseous or liquid states, i.e., will not becomesolidified. Apart from this, the low end of the temperature rangemaintained within the reactor will usually depend upon the desiredprocess economics since some reactions will be unacceptably slow if thetemperature is maintained too low.

The upper end of the temperature range maintained within the reactorwill usually be from about 5° C. to about 200° C. below that temperatureat which significant product degradation or undesirable side productformation occurs. By "significant" is meant 10% or more of the productdegrades or 10% or more of the reaction product comprises the product ofa side reaction.

Usually the temperature within the reactor will be within a range offrom about -50° C. to about 500° C. (depending upon the particularreactants), preferably from about 0° C. to about 400° C. (againdepending upon the particular reactants) and more preferably betweenabout 110° and 400° C. (depending upon the particular reactants). Forexample, the reactor will be maintained within a range of from about100° C. to about 200° C. for an ethoxylation reaction, while for atypical sulfonation process, the reactor temperature maintained within arange of from about -20° C. to about +100° C.

The outlet pressure of the reactor may be maintained at any conventionalpressure used in state of the art reactors consistent with the minimumpressure needed to obtain sufficient desired product flow up to themaximum pressure which may be handled by downstream equipment, e.g., ahigh pressure needed to couple with downstream processing.

Inlet pressures of the reactants must be consistent with the desiredoutlet pressure and the pressure drop within the reactor. Thedifferential in inlet pressure between the first and second reactantswill be a function of the permeability of the second reactant--whichwill, in turn, be dependent upon the physical properties of the secondreactant and the porosity of the porous material in the apparatus.

It should be noted that the pressure within the second reaction zone atall locations of the porous wall should be maintained higher than thepressure in the first reaction zone at corresponding locations of theporous wall, to thereby inhibit any flow through the porous wall fromthe first reaction zone to the second reaction zone.

Reactions and Reactants Used in the Process

There are many exothermic reactions which benefit from the applicationof this invention. By way of examples of reactions which may be carriedout using the process and apparatus of the invention, and not by way oflimitation, there may be mentioned oxidations, halogenations,sulfonations, sulfations, nitrations, ethoxylations, hydrogenations,polymerizations and the like. State of the art conditions for thesereactions, therefore, extend over very broad ranges of temperature andpressure.

To practice the present invention with these exothermic conditions, oneof skill in the art should select the conditions for the reaction firstzone to be quite near those conditions used with state of the artreactors for the reactions considered. The advantage of using thepresent invention is less local temperature excursions within thereactor, and better control of the transport of reactants and productsthroughout the reaction zone and process yielding higher quality, andmore uniform reaction products.

The respective flow rates of the reactants into the reactor will, ofcourse, depend upon a number of parameters including those justdiscussed, as well as the overall size of the reactor. The relativerates of reactant flow, i.e., with respect to one another, will dependupon the particular reaction, including the amount of heat generated, aswell as whether or not the process will be carried out in one or morestages.

It may be desirable, when the process is conducted in a single stageapparatus, to circulate some of the product stream back to the inletside of either or both reactants in some instances to thereby provide afurther control of the reaction rate or to alter the viscosity of one ofthe incoming reactant flows. In the case of the first reactant 3, suchdilution will result in less reactant present per given mass and heatcapacity of this total flow going into the zone 1 of the reactor. Thus,the total exothermic heat of the reactions of all of this first reactantmixture 3 will result in a lower final temperature because of the largerheat capacity. Addition of the product to the second reactant stream 4will (in many cases) serve to increase the viscosity of the secondreactant stream passing through the porous barrier, thus decreasing thevolumetric flow rate of second reactant passing through the porousbarrier (in accordance with the previous equation) which will also serveto slow down the reaction and reduce the generation of exothermic heat.

Multiple Stage Apparatus for Conducting the Process

The preferred mode of operating the process of the invention will be ina plurality of stages, using, for example, in each stage, a shell andtube reactor such as previously described and illustrated in FIGS. 2 and3, together with optional recirculation of product, optional addition ofmakeup reactants, and optional use of heat exchangers to control theoverall temperature buildup as needed.

Such apparatus is illustrated in block diagram form in FIG. 4 whichillustrates three stages of operation of the process of the invention.The first reactant from source 70 travels via conduit 72 through valve74 and pump 76 to an optional mixer 78 where the first reactant stream 3may be optionally blended with a portion of the product stream fromfirst reactor 100. The first reactant 3 then travels via conduit 79 intofirst reactor 100, which may be a shell and tube reactor similar toreactor 40 previously depicted in FIGS. 2 and 3. In this case, conduit79 would be connected to inlet manifold 44 (FIG. 2) within reactor 100so that the first reactant 3 flows through the tubes containing mixingelements within reactor 100 connected to inlet manifold 44.

The second reactant 4, from second reactant source 80, passes viaconduit 82 through valve 83 and then through conduit 84 to optionalblender 89 and then through conduit 85 to enter the shell portion offirst reactor 100. As previously described with respect to FIGS. 2 and3, the second reactant 4 then passes from the shell through the porousportions of the tubes within reactor 100 to react with the firstreactant 3 flowing through the tubes.

The resulting product 5, as well as any unreacted reactant(s), leavefirst reactor 100 via conduit 86, where the product stream splits intotwo streams. Conduit 87a optionally returns some of the product streamthrough valve 88a to optional blender 89 where it is blended with thesecond reactant stream and is then fed via conduit 85 into reactor 100.The remainder of the product stream passes through conduit 87b to valve88b and then through heat exchanger 81 and conduit 90. Conduit 90 thenalso splits into two portions. Conduit 92 passes a portion of theproduct stream to the next stage, and conduit 94 through which one mayoptionally recirculate product 5 back to reactor 100.

The portion of the product stream optionally recycled back to reactor100 through conduit 94 passes through a valve 95 (which controls theratio of product stream being recycled back to reactor 100) to pump 96which is connected to mixer 78 via conduit 98.

By shutting off both valves 88a and 95, all of the product stream willbe passed on to the subsequent stage of the apparatus, shutting off onlyone of valves 88a or 95 will respectively recycle the product streamback to only one of the initial reactant streams as desired.

Similarly, the relative flows of the first and second reactants intoreactor 100 may be controlled by adjustment of valves 74 and 83, as wellas valve 88b, either by itself (when valve 88a is shut off) or inconjunction with valve 88a, to control the flow rate through reactor100.

The portion of the product stream to be passed on to the next stage vialine 92 passes through pump 176 to optional mixer 178 where it isoptionally blended with recycled product from the second stage as wellas with an optional flow of further first reactant from first reactantsource 70 via line 172 and valve 174, which controls the amount of freshfirst reactant to be blended with the product stream from reactor 100.

The product stream from reactor 100, with or without further amounts offresh first reactant and recycled product from the second stage, is fedinto second reactor 200 via line 179. As previously described withrespect to reactor 100, second reactor 200 would preferably beconstructed similarly to reactor 40 illustrated in FIGS. 2 and 3, so theincoming stream from line 179 would pass into the interior of the poroustubes of the reactor via the inlet manifold.

Optional additional second reactant would then flow, via line 182 andvalve 183 from second reactant source 80 to an optional blender 189 fromwhich it would flow via conduit 185 to the shell side of reactor 200.

The product stream, emerging from reactor 200 via conduit 186, is splitinto two streams (as in the first stage). One stream which will flow viaconduit 187a through valve 188a to optional blender 189 where it can beblended with fresh second reactant. The other stream will flow viaconduit 187b to valve 188b and heat exchanger 181. The stream then flowsvia conduit 190 to a point where it again may be split between twostreams to either pass on to the third stage via conduit 192 or torecirculate via conduit 194 and valve 195 back through pump 196 andconduit 198 to optional blender 178 where the product stream may beblended with fresh first reactant 3.

Similarly, in the third stage, the product stream in conduit 192 may bepumped through pump 276 to optional blender 278 where it may beoptionally blended with fresh first reactant 3 entering blender 278 fromsource 70 via conduit 272 and valve 274, as well as with recycledproduct from reactor 300, as will be described below, before enteringreactor 300 via conduit 279. Reactor 300 is also preferably beconstructed in accordance with the previously described constructionwith respect to FIGS. 2 and 3. Thus, the incoming stream via conduit 279enters the inlet manifold to be distributed to the porous tubes withinreactor 300.

Optional additional second reactant 4 would then flow, via line 282 andvalve 283 from second reactant source 80 to optional blender 289 fromwhich it would flow via conduit 285 to the shell side of reactor 300.

The product stream, emerging from reactor 300 via conduit 286, is thensplit into two streams (as in the first and second stages). One streamwhich will flow via conduit 287a through valve 288a to optional blender289 where it can be blended with fresh second reactant 4. The otherstream will flow via conduit 287b to valve 288b and heat exchanger 281.It then flows by way of conduit 290 to a point where it again may besplit between two streams to either pass on to the product collectionpoint 350 via conduit 292 or to recirculate via conduit 294 and valve295 back through pump 296 and conduit 298 to optional blender 278 wherethe product stream may be again blended with fresh first reactant 3.

It should be noted that while the above description of a multiple stageapparatus includes descriptions of valves and conduits which makepossible the recycling of portions of the product flow back to eachreactor stage and which also make possible the blending of fresh firstor second reactants at every stage, these options will rarely all beexercised simultaneously. Thus, it may be possible that no product willbe recycled and no fresh first or second reactants added, with thesubsequent stages merely acting as an extension of the reaction zone ofthe first stage. Alternatively, when stoichiometric equivalents of bothreactants have been initially fed into the first stage, only therecycling of product may be carried out, without any additional amountsof either reactant added to the streams entering the subsequent stagesof the apparatus. Finally, if a stoichiometric excess of one of thereactants is initially fed into the first stage, only significantamounts of the other reactant may be blended with the inlet streams tosubsequent stages. However, even in such circumstances, it may benecessary to add to subsequent stages minor increments of even thereactant initially added in stoichiometric excess to the first stage.

As shown in the dotted lines in FIG. 4, connected respectively toreactors 100, 200, and 300, optional heat exchanger loops, eachcomprising a heat exchanger changer 316, and a pump 320, may beconnected to one or more of the reactors to remove exothermic heatgenerated in any or all of the reactors as needed.

In the sulfonation of the methyl laurate (or other alkyl long chainesters), the sulfur trioxide to methyl laurate feed ratio is betweenabout 0.8 and 1.2 (preferably 1.05). The sulfonation reactor outlettemperature is between about 60° and 100° C. (preferably about 74°-75°C.). The sulfonation pressure of the inlet is between about 250 and 350psia (1.7×10⁶ and 2.4×10⁶ pascal) preferably about 300-306 psia (about2.1 and 10⁶ pascal). The outlet pressure is between about 50 and 100psia (3.4×10⁴ and 6.9×10⁴ pascal), preferably about 65 psia (4.4×10⁴pascal). The residence time in the reactor is between about 1 and 4 sec.(preferably about 2.3 sec.). The conversion of methyl laurate is high,generally between about 90-99% (usually about 97-98%). The selectivityto produce alpha-sulfomethyl laurate is high, generally between about 90and 99% (usually about 95-96%).

In one embodiment, a reactor of the present invention has an overallshell size of about 40-60 in (100-150 cm) in length, preferably about 45in (114 cm), and a diameter of about 15-25 in (38-63 cm), preferably19-20 in (48-51 cm). The number of porous tubes is between about 150 and220 (preferably about 189-190). The porous tubes have between about0.6-2.54 cm inside diameter (I.D.) (preferably about 1.6 cm) and anoutside diameter (O.D.) of between about 1.27 and 3.8 cm, preferablyabout 2.2 cm. The reactor has between about 75 and 125 cm of activelength, preferably about 100 cm. The mixing elements and mixing ballshaving a diameter of between about 0.5 and 0.1 cm, preferably about 0.25cm.

Pulsatile Flow

In one embodiment referring to FIGS. 1 and 3, the exothermic reactorprocess uses, with the first reactant 3, a slurry of a catalyst 12A inreactor 10. The flow of catalyst slurry 12A with the mixing elements 12occurs such that the flow rate of the first reactant 3 changes as afunction of time. This flow rate change may be referred to as pulsatile(or pulsed) flow e.g. a sine wave, square wave, irregular wave, etc..The pulsed flow prevents the accumulation of solid catalyst particles12A at fixed points on the mixing elements 12. This accumulation ofcatalyst particles 12A is not desired because it changes the flowcharacteristics in mixing in the reaction zone and may ultimately blockthe flow of catalyst or reactant or both.

Preferably, the pulsed flow changes with time in a cyclic manner. Forinstance, the rate of flow of catalyst slurry may change in the cyclefrom maximum flow to a level of about 80% of the maximum rate of flow.Preferably, the rate of flow of catalyst slurry cycles down to a levelof about 50% of the maximum rate of flow of the catalyst slurry, thenreturns to the maximum flow rate. Preferably, the rate of flow ofcatalyst slurry cycles down to a level of about 20% in the reversedirection of the maximum rate of flow of the catalyst 12A, then returnsto about the maximum flow rate in the original direction of flow.

In the pulsed flow, a typical example is the reaction of hydrogen withan alkene using a flowing slurry of Raney nickel catalyst particlessuspended in the alkane. The maximum rate of flow of the reactantsuspended catalyst corresponds to residence times of between about 0.5to 6000 sec. The flow rate can change to achieve a rate of flow ofbetween about 80% and -20% ml/sec. of maximum. After remaining at thisreduced flow rate (about 50% of maximum) for between about 0.1 and 1000sec, the rate of flow is increased back to the maximum flow rate.

Separation (e.g., Evaporation) of Reaction Products

In one embodiment, the present invention is improved by removal ofvolatile reaction products. The volatile reaction products or reactantsare those having a vapor pressure of about 1 mm of Hg or higher at thereaction temperature of the reaction of step (c). Referring now to FIGS.2 and 8, reactor 40 is one having a shell 60 and having multi tubeporous barrier reactors 50. The second reactant 4 enters through inlet62 via line 62A and is forced under pressure from the shell side throughthe porous barrier 52 into a recirculation stream of product 48A. Thesecond reactant can be removed or recycled via line 64A at outlet 64.The first reactant is introduced to the reactor 60 via inlet 42 via line42A in a continuous (or a pulsed) stream in the tube side of thereactor. A recycle loop of lines 48A and 48B, evaporator 500, and line48D has a flash evaporator 500 to remove the volatile products of thereaction. The reaction products (or multiple components) is conveyedfrom outlet 48 via line 48A and 48B to an optional cooler 501 and thenas a liquid via line 48B to the evaporator 500. The volatile reactionproducts are removed as a vapor via line 48C. The liquid product isconveyed via line 48D to line 42A, and then is recycled through theprimary reactor 40. In effect, a steady state loop is created formaximum heat removal. The volatile reaction products are removed whichprevents their further reaction and the formation of undesirable sideproducts, and usually permits the operation of the primary reactor athigher temperatures, as compared to the system which does not have theevaporator, e.g. from about 520 C. up to about 200° C. higher than thereaction systems not having the evaporator.

The fields of use for the present invention include, but are not limitedto, formation of a pesticide, a fungicide, a rodenticide, aninsecticide, a herbicide, a pharmaceutical, a surfactant, a demulsifyingagent, a fabric treatment agent, a hydrocarbon solvent, a hydrocarbonfuel, an organic polymer, a synthetic lubricant, a halogenatedhydrocarbon, a fire retardant and the like.

Surfactants which are prepared according to the present invention,include but are not limited to, alkyl benzene sulfonates, linearalkylbenzene sulfonates, secondary alkane sulfonates, alpha olefinsulfonates, alkyl glyceryl ether sulfonates, methyl ester sulfonates,natural fat sulfonates, alcohol sulfates, alcohol ether sulfates and thelike.

The following examples serve to further explain and describe the presentinvention. They are not to be construed to be limiting in any way.

EXAMPLE I

Ester Sulfonation (SO₃ High Flow Rate)

(a) Fresh methyl laurate, having a viscosity of 2 cp, may be fed at arate of 550 grams/sec into a mixer where it is mixed with a 5650grams/sec flow of recycled product and the resulting mixture is fed, ata temperature of about 38° C. (˜100° F.) and a pressure of about 340psia (2.3×10⁶ pascal (where 1 psia--6894.7 pascal)) into the top of 85porous wall tubes arranged vertically in a bundle in a cylindricalreactor having an inside diameter (ID) of about 20 in. (50.8 cm) Eachtube has an ID of about 3/4" (1.91 cm), and has a 110 cm. length ofporous metal comprising stain-less steel fabricated by powder metallurgyto have a nominal pore size of generally about 0.2 microns (μmeters) anda viscosity normalized permeance of about 0.0037 cm³ cp/cm² sec psi.

The tubes are each packed with inert glass balls, each having a diameterof 0.320 cm., up to a distance of 10 cm. above the porous portion ofeach tube and also extending to the bottom of each tube, i.e., beyondthe porous portion of the tube in the direction of reactant flow.

On the shell side of the reactor, 205 grams/second of liquid SO₃ may bemixed with a 760 grams/sec flow of recycled product at a temperature ofabout 38° C. (˜100° F.) and a pressure of about 350 psia (2.4×10⁶pascal) and fed into the shell portion of the reactor to pass throughthe porous tubes and react with the methyl laurate therein.

The resulting product stream, leaving the reactor at a temperature ofabout 74° C. (˜165° F.) and a pressure of about 65 psia (4.5×10⁵pascal), is fed through a heat exchanger containing 1350 tubes having anID of 1.91 cm and 240 cm in length, and also packed with 0.32 cmdiameter inert glass balls.

The sulfonated methyl laurate product from such a reactor system will beuniform and low in unwanted products and substantially higher in qualitythan that obtained from state of the art reactor technology. This isbecause there is no temperature peak typical of the entry region of afalling film reactor and because there is even distribution of reactantall along the reactor length in the process of the invention.

(b) Similarly, the reaction described in Example 1 (a) above is repeatedexcept that the methyl laurate is replaced by a stoichiometricallyequivalent amount of linear alkylbenzene, the corresponding linearalkylbenzenesulfonic acid is obtained. These are useful as surfactants.

(c) Similarly, the reaction described in Example I (a) above is repeatedexcept that the methyl laurate is replaced by a stoichiometricallyequivalent amount of phenol, and the corresponding mixture ofhydroxybenzenesulfonic acids are obtained.

EXAMPLE II

Ester Sulfonation (SO₃ Lower Flow Rate)

(a) Fresh methyl laurate, having a viscosity of 2 cp, may be fed at arate of 550 grams/second into a mixer where it is mixed with a 6400grams/sec flow of recycled product and the resulting mixture is fed, ata temperature of about 38° C. (˜100° F.) and a pressure of about 265psia (1.8×10⁶ pascal) into the top of 125 porous wall tubes arrangedvertically in a bundle in a cylindrical reactor having an ID of about 20inches. Each tube has an ID of about 3/4" (1.91 cm), and has a 110 cm.length of porous metal comprising stainless steel fabricated by powdermetallurgy and coated with zirconia to have a viscosity normalizedpermeance of about 1.2×10⁻⁵ cm³ cp/cm² sec psi.

The tubes are each packed with inert glass balls, having a diameter of0.320 cm., up to a distance of 10 cm. above the porous portion of eachtube and also extending to the bottom of each tube, i.e,, beyond theporous portion of the tube in the direction of reactant flow.

On the shell side of the reactor, liquid SO₃ may be introduced into thereactor, without mixing with recycled product, at a flow rate of about205 grams/sec flow, and at a temperature of about 38° C. (˜100° F.), anda pressure of about 350 psia (2.4×10⁶ pascal) to pass through the poroustubes and react with the methyl laurate therein.

The resulting product stream leaving the reactor at a temperature ofabout 74° C. (˜165° F.) and a pressure of about 65 psia (4.5×10⁵ pascal)is fed through a heat exchanger similar to that described in Example I.The resulting sulfonated methyl laurate product will again be uniformand low in unwanted products and substantially higher in quality thanthat obtained from state of the art reactor technology.

(b) Similarly, the reaction described in Example II (a) above isrepeated except that the methyl laurate is replaced by astoichiometrically equivalent amount of linear alkylbenzene, thecorresponding linear alkylbenzenesulfonic acid is obtained.

(c) Similarly, the reaction described in Example II(a) above is repeatedexcept that the methyl laurate is replaced by a stoichiometricallyequivalent amount of phenol, and the corresponding mixture ofhydroxybenzenesulfonic acids are obtained.

EXAMPLE III

Ester Sulfonation, Multiple Stages

(a) To illustrate the use of multiple stages of the process of theinvention, when products with particularly low levels of impurities aredesired, three shell and tube reactors similar to those used in ExamplesI and II may be used. The porous wall portion of each tube would be 110cm in length and the inner diameter of each would be 1.91 cm (3/4). Theporous portion of each tube may be fabricated from a stainless steelpowder metallurgy and coated with zirconia to provide a viscositynormalized permeance of 1.2×10⁻⁵ cm³ cp/cm² sec psi and each tube couldbe filled with 0.32 cm diameter inert glass balls to 10 cm above andbelow the porous portion of the tube. In each reactor, the tubes wouldbe located in a 50.8 cm (20 in) diameter shell. Each reactor may beconnected to a heat exchanger having tubes with a diameter of 1.91 cm IDfilled with the same inert 0.32 cm diameter spherical glass mixingelements used in the reactors. The length of the tubes could be variedfor different stages.

In the first stage, a 550 grams/sec flow of fresh methyl laurate may bemixed with 2900 grams/sec of cooled recycled product from the firststage and introduced into a 46 tube reactor first stage at a temperatureof 38° C. (100° F.) and a pressure of 155 psia (1.1×10⁶ pascal).

About 50% (103 grams/sec) of the total SO₃ is introduced as a liquidinto the shell side of the first stage reactor at 350 psia and atemperature of 38° C. The resultant product flow, having a temperatureof about 74° C. (165° F.) and a pressure of 65 psia (4.5×10⁵ pascal), isfed into a heat exchange containing 45 of the 0.6 meter long tubesfilled with mixing elements.

From the output of the first stage heat exchanger, 655 grams/sec ismixed with 1775 grams/sec of cooled product stream from the second stageand fed into 36 tubes comprising the second stage reactor at atemperature of 38° C. (100° F.) and 200 psia (1.4×10⁶ pascal). The other2900 grams/sec of cooled product from the first stage may be recycledback to the first stage reactor as described above.

About 35% (72 grams/sec) of the total amount of SO₃ is introduced as aliquid into the shell side of the second stage reactor at 350 psia(2.4×10⁶ pascal) which will result in a product flow exiting the secondstage reactor at 65 psia (4.5×10⁵ pascal) and a temperature of 74° C.(165° F.). This product flow is then cooled by feeding it into 115 1.3meter long mixing element-filled tubes in the second stage heatexchanger.

From the second stage recirculating loop downstream of the second stageheat exchanger, 725 grams/sec of product flow is mixed with 320grams/sec of cooled product from the third stage and introduced into the19 tube third stage reactor at a temperature of 38° C. (100° F.) and apressure of 265 psia (1.8×10⁶ pascal). In this stage the remaining 15%of the SO₃ is introduced at a temperature of 38° C. and a pressure of115 psia (1.1×10⁶ pascal).

The product flow from the third stage reactor tubes leaves the reactorat 65 psia and 74° C. (165° F.) and enters a heat exchanger containing200 of the 2.3 meter tubes which are also filled with mixing elements.From the recirculating loop coming from this third heat exchanger, 760grams/sec of product are withdrawn, while the remaining 320 grams/sec ofcooled product are recycled as previously described.

The resulting sulfonated methyl laurate product will again be uniformand low in unwanted products and substantially higher in quality thanthat obtained from state of the art reactor technology.

(b) Similarly, the reaction described in Example III (a) above isrepeated except that the methyl laurate is replaced by astoichiometrically equivalent amount of linear alkylbenzene, thecorresponding linear alkyibenzenesulfonic acid is obtained.

(c) Similarly, the reaction described in Example III (a) above isrepeated except that the methyl laurate is replaced by astoichiometrically equivalent amount of phenol, and the correspondingmixture of hydroxybenzenesulfonic acids are obtained.

EXAMPLE IV

Ester Sulfonation, Small Temperature Increase

(a) To illustrate a modification of the process of the invention, whereall of the SO₃ is introduced in one stage with a very low rise intemperature because of the high recycle rate, and a second stage isprovided operating at a substantially higher temperature to allow anyrearrangement of SO₃ among the molecules in the product from the firstreactor stage, methyl laurate may be introduced into a reactorcontaining 200 tubes, each having the same dimensions and viscositynormalized permeance as in Example II.

The flow rate of fresh methyl laurate is also the same as in Example II,i.e, 550 grams/sec, but the amount of recycled product blended with themethyl laurate prior to introduction into the tubes is 10,750grams/second, i.e., much higher than Example II, resulting in morethermal mass and, therefore, a commensurate reduction in the temperaturerise from the fixed exothermic heat generated. The combined streamenters the tubes of the reactor at 38° C. (100° F.) and 285 psia(1.96×10⁶ pascal).

On the shell side of the reactor a stream of 205 grams of liquid SO₃ isintroduced into the reactor at a temperature of 38° C. (100° F.) and apressure of 290 psia (2.0×10⁶ pascal).

The product flow exiting the reactor then is circulated through the samemixing element-filled heat exchanger as in Example I and a product flowof about 760 grams/sec is withdrawn from output of the heat exchanger(with the balance recycled back to the reactor), mixed with a flow ofabout 6000 grams/sec of recycled product from a mixing tank, and pumpedto the tube side of a heat exchanger where it is heated to have an exittemperature of 82° C. (180° F.). This flow goes to the mixing tank whichis sized to have a residence time of about 15 minutes. This time atelevated temperature allows any rearrangement of the materials in theproduct to closely approach equilibrium. The product is continuouslywithdrawn from the mixing tank at 760 grams/sec and cooled for storageor use.

In this regard, it should be noted that such a mixing tank is filledwith the product from the last operation. The first time the apparatusis started, the tank is filled from the low temperature reactor. Themixing tank can have any type of stirring or agitation means within it,including mixing elements. For example, some molecules could contain twoattached SO₃ groups and other molecules have no SO₃ groups attached. Thebreaking of a SO₃ group away from a molecule with two such groups andthe combination of an SO₃ group with a molecule without an SO₃ group onit would not generate substantial net heat in the mixing tank.

Again, the resulting product will be uniform and low in unwantedproducts and substantially higher in quality than that obtained fromstate of the art reactor technology.

(b) Similarly, the reaction described in Example IV (a) above isrepeated except that the methyl laurate is replaced by astoichiometrically equivalent amount of linear alkylbenzene thecorresponding linear alkylbenzenesulfonic acid is obtained.

(c) Similarly, when the reaction described above in Example IV (a) isrepeated except that the methyl laurate is replaced by astoichiometrically equivalent amount of phenol, the correspondingmixture of hydroxybenzenesulfonic acids are obtained.

EXAMPLE V

Alcohol and Ethylene Oxide

(a) Fresh tridecyl alcohol, having a viscosity of 1 cp, may be fed at arate of 270 grams/second into a mixer where it is mixed with a 12,300grams/sec flow of recycled product and the resulting mixture is fed, ata temperature of about 121° C. (˜250° F.) and a pressure of about 80psia (5.5×10⁵ pascal) into the top of 585 porous wall tubes arrangedvertically in a bundle in a cylindrical reactor having an ID of about 30inches. Each tube has an ID of about 5/8" (1.59 cm), and has a 100 cm.length of porous metal comprising stainless steel fabricated by powdermetallurgy and coated with zirconia to have a viscosity normalizedpermeance of about 1.2×10⁻⁵ cm³ cp/cm² sec psi.

The tubes are each packed with inert glass balls, having a diameter of0.265 cm., up to a distance of 10 cm. above the porous portion of eachtube and also extending to the bottom of each tube, i.e., beyond theporous portion of the tube in the direction of reactant flow.

On the shell side of the reactor, gaseous ethylene oxide may beintroduced into the reactor, without mixing with recycled product, at aflow rate of about 532 grams/sec flow, and at a temperature of about121° C. (˜250° F.), and a pressure of about 250 psia (1.7×10⁶ pascal) topass through the porous tubes and react with the tridecyl alcoholtherein.

The resulting product stream leaving the reactor at a temperature ofabout 199° C. (˜300° F.) and a pressure of about 65 psia (4.5×10⁵pascal) is fed through a heat exchanger similar to that described inExample I. The resulting ethoxylated tridecyl alcohol product will havea very unitary product distribution and be low in unwanted products andsubstantially higher in quality than that obtained from state of the artreactor technology.

Thus, the present invention provides a process for carrying out anexothermic process wherein the flow of second reactant into the reactionzone is controlled, to thereby control the reaction and the amount ofexothermic heat generated, by the use of a porous barrier whichrestricts the amount of second reactant flowing across the porousbarrier into the reaction zone. Such control of the reaction andgeneration of exothermic heat, while providing adequate mixing of thereactants in the reaction zone to ensure homogeneous reaction and heatgeneration in the reaction zone, results in a product which, asmentioned above in the examples, is uniform and low in unwanted productsand substantially higher in quality than that obtained from state of theart reactor technology.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art of chemical processing and control of an exothermic reactionin a reaction zone by use of a porous barrier between a first reactantand a second reactant having mixing elements in the reaction zone asdescribed herein. The use of a porous barrier and mixing elements inchemical processing applications is such that various changes may bemade and equivalents may be substituted without departing from the truespirit and scope of the present invention. In addition, manymodifications may be made to adapt a particular situation, material, orcomposition of matter, process, process step or steps, or the presentobjective to the spirit and scope of this invention, without departingfrom its essential teachings.

We claim:
 1. A process for forming a reaction product fluid by reactionof one or more first reactants and one or more second reactants, whichprocess comprises:(a) feeding into a first reactor zone having mixingelements therein said one or more first reactants at a first pressure;(b) feeding one or more of said second reactants at a second pressurehigher than said first pressure into a second reactor zone which isseparated from said first reactor zone by a porous wall which is capableof being penetrated by said second reactant at multiple sites to producein said first reactor zone a resulting mixture having componentsselected from the group consisting of said reaction product fluid,unreacted said first reactant, unreacted said second reactant andcombinations thereof; and (c) maintaining the pressure within saidsecond reaction zone higher than the pressure in said first reactor zoneat corresponding locations along the length of said porous wall, tothereby inhibit any flow of the components of said first reactor zonewhich are selected from the group consisting of said reaction productfluid, unreacted said first reactant, unreacted second reactant andcombinations thereof through said porous wall from said first reactorzone to said second reactor zone; wherein said one or more secondreactants pass once through said porous wall to contact said one or morefirst reactants in said first reactor zone and form said reactionproduct fluid comprising a liquid, a gas or combinations thereof in saidfirst reactor zone, and the components of said first reactor zone whichare selected from the group consisting of said reaction product fluid,unreacted said first reactant, unreacted said second reactant andcombinations thereof exit only from said first reactor zone, whereinsaid porous wall through which said one or more second reactants passesinto said first reactor zone has a viscosity normalized permeabilityranging from about 10⁻⁶ to about 5×10⁻² cm³ cp/cm² sec psi.
 2. Theprocess of claim 1 wherein a portion of the product flow from saidreactor is recycled back and blended with said one or more firstreactants being fed into said first reactor zone.
 3. The process ofclaim 1 wherein a portion of the product flow from said reactor isrecycled back and blended with said one or more second reactants beingfed into said second reactor zone.
 4. The process of claim 1 wherein atleast one of said reactants is a liquid.
 5. The process of claim 4wherein at least one of said one or more said first reactants is aliquid.
 6. The process of claim 4 wherein at least one of said one ormore second reactants is a liquid.
 7. The process of claim 4 wherein atleast one of said one or more first reactants is a liquid and at leastone of said one or more second reactants is a liquid.
 8. The process ofclaim 1 wherein the temperature of each of said reactants being fed intothe respective reaction zones is within a range of from about -50° C. toabout 500° C.
 9. The process of claim 1 wherein the pressure of each ofsaid first reactants and said second reactants being fed into therespective reaction zones is within a range of from about 14 psia toabout 1000 psia, with the pressure of said one or more second reactantsbeing greater than the pressure of said one or more first reactants. 10.The process of claim 1 wherein all or a portion of said product isrecycled back to said first reactor zone.
 11. The process of claim 10wherein all or a portion of said product is cooled and then recycledback to said first reactor zone.
 12. The process of claim 1 wherein saidporous wall comprises one or more porous tubes which separate said firstreactor zone from said second reactor zone.
 13. A process for forming areaction product fluid by reaction of one or more first reactants andone or more second reactants, which process comprises:(a) feeding into afirst reactor zone having mixing elements therein said one or more firstreactants at a first pressure; (b) feeding one or more of said secondreactants at a second pressure higher than said first pressure into asecond reactor zone which is separated from said first reactor zone by aporous wall which is capable of being penetrated by said second reactantat multiple sites to produce in said first reactor zone a resultingmixture having components selected from the group consisting of saidreaction product fluid, unreacted said first reactant, unreacted saidsecond reactant and combinations thereof; and (c) maintaining thepressure within said second reaction zone higher than the pressure insaid first reactor zone at corresponding locations along the length ofsaid porous wall, to thereby inhibit any flow of the components of saidfirst reactor zone which are selected from the group consisting of saidreaction product fluid, unreacted said first reactant, unreacted secondreactant and combinations thereof through said porous wall from saidfirst reactor zone to said second reactor zone; wherein said one or moresecond reactants pass once through said porous wall to contact said oneor more first reactants in said first reactor zone and form saidreaction product fluid comprising a liquid, a gas or combinationsthereof in said first reactor zone, and the components of said firstreactor zone which are selected from the group consisting of saidreaction product fluid, unreacted said first reactant, unreacted saidsecond reactant and combinations thereof exit only from said firstreactor zone, wherein said product flow from said reactor is firstpassed through a heat exchanger before said portion of said product flowis recycled back and blended with said one or more first reactants beingfed into said first reactor zone, wherein said porous wall through whichsaid one or more second reactants passes into said first reactor zonehas a viscosity normalized permeability ranging from about 10⁻⁶ to about5×10⁻² cm³ cp/cm² sec psi.
 14. A process for forming a reaction productfluid by reaction of one or more first reactants and one or more secondreactants, which process comprises:(a) feeding into a first reactor zonehaving mixing elements therein said one or more first reactants at afirst pressure; (b) feeding one or more of said second reactants at asecond pressure higher than said first pressure into a second reactorzone which is separated from said first reactor zone by a porous wallwhich is capable of being penetrated by said second reactant at multiplesites to produce in said first reactor zone a resulting mixture havingcomponents selected from the group consisting of said reaction productfluid, unreacted said first reactant, unreacted said second reactant andcombinations thereof; and (c) maintaining the pressure within saidsecond reaction zone higher than the pressure in said first reactor zoneat corresponding locations along the length of said porous wall, tothereby inhibit any flow of the components of said first reactor zonewhich are selected from the group consisting of said reaction productfluid, unreacted said first reactant, unreacted second reactant andcombinations thereof through said porous wall from said first reactorzone to said second reactor zone; wherein said one or more secondreactants pass once through said porous wall to contact said one or morefirst reactants in said first reactor zone and form said reactionproduct fluid comprising a liquid, a gas or combinations thereof in saidfirst reactor zone, and the components of said first reactor zone whichare selected from the group consisting of said reaction product fluid,unreacted said first reactant, unreacted said second reactant andcombinations thereof exit only from said first reactor zone, wherein aportion of the product flow from said reactor is recycled back andblended with said one or more second reactants being fed into saidsecond reactor zone, and, wherein said product flow from said reactor isfirst passed through a heat exchanger before said portion of saidproduct flow is recycled back and blended with said one or more secondreactants being fed into said second reactor zone, wherein said porouswall through which said one or more second reactants passes into saidfirst reactor zone has a viscosity normalized permeability ranging fromabout 10⁻⁶ to about 5×10⁻² cm³ cp/cm² sec psi.
 15. A process for forminga reaction product fluid by reaction of one or more first reactants andone or more second reactants, which process comprises:(a) feeding into afirst reactor zone having mixing elements therein one or more firstreactants at a first pressure; (b) feeding one or more second reactantsat a second pressure higher than said first pressure into a secondreactor zone separated from said first reactor zone by a porous wallwhich is capable of being penetrated by said one or more secondreactants at multiple sites to produce in said first reactor zone aresulting mixture having components selected from the group consistingof said reaction product fluid, unreacted said first reactant, unreactedsaid second reactant and combinations thereof; and (c) maintaining thepressure within said second reaction zone higher than the pressure insaid first reaction zone at corresponding locations of said porous wall,to thereby inhibit any flow of the components of said first reactor zonewhich are selected from the group consisting of said reaction productfluid, unreacted said first reactant, unreacted second reactant andcombinations thereof through said porous wall from said first reactorzone to said second reactor zone; wherein said one or more secondreactants pass through said porous wall to contact said one or morefirst reactants in said first reactor zone and form said reactionproduct fluid comprising a liquid, a gas or combinations thereof in saidfirst reactor zone, and the components of said first reactor zone whichare selected from the group consisting of said reaction product fluid,unreacted said first reactant, unreacted said second reactant andcombinations thereof exit only from said first reactor zone, and thetemperature of the reaction is between about 0° and 400° C., whereinsaid porous wall through which said one or more second reactants passesinto said first reactor zone has a viscosity normalized permeabilityranging from about 10⁻⁶ to about 5×10⁻² cm³ cp/cm² sec psi.
 16. Theprocess of claim 1 wherein said mixing elements in said first reactorzone have at least one dimension which is equal to from about 1/2 toabout 1/100 of the largest dimension of said first reactor zone whereinsaid one dimension and said largest dimension are measured in thedimension which is perpendicular to the flow of said one or more firstreactants through said first reactor zone.
 17. The process of claim 16wherein said mixing elements in said first reactor zone have at leastone dimension equal to from about 1/3 to about 1/10 of the largestdimension of said first reactor zone normal to the flow of said one ormore first reactants through said first reactor zone.
 18. The process ofclaim 15 wherein said porous wall comprises one or more porous tubeswhich separate said first reactor zone from said second reactor zone.19. The process of claim 1 wherein the reaction occurring in zone one isselected from the group consisting of oxidation, sulfonation,hydrogenation, halogenation, ethoxylation, sulfation, nitration, andpolymerization.
 20. The process of claim 1 wherein the reaction isoxidation.
 21. The process of claim 1 wherein the reaction issulfonation.
 22. The process of claim 1 wherein the reaction ishydrogenation.
 23. The process of claim 1 wherein the reaction ishalogenation.
 24. The process of claim 1 wherein the reaction isnitration.
 25. The process of claim 1 wherein the reaction ispolymerization.
 26. An exothermic process for forming a reaction productfluid by reaction of one or more first liquid reactants with one or moresecond liquid reactants, which process comprises:(a) feeding one or morefirst liquid reactants at a first pressure through a first reactor zonehaving mixing elements therein; (b) feeding one or more second liquidreactants at a second pressure higher than said first pressure into asecond reactor zone which is separated from said first reactor zone by aporous wall which is capable of being penetrated at multiple sites toproduce in said first reactor zone a resulting mixture having componentsselected from the group consisting of said reaction product fluid,unreacted said first reactant, unreacted said second reactant andcombinations thereof; and (c) maintaining the pressure within saidsecond reaction zone higher than the pressure in said first reactionzone at corresponding locations of said porous wall, to thereby inhibitany flow of the components of said first reactor zone one which areselected from the group consisting of said reaction product fluid,unreacted said first reactant, unreacted second reactant andcombinations thereof through said porous wall from said first reactorzone to said second reactor zone; wherein said one or more second liquidreactants pass once through said porous wall to contact said one or morefirst liquid reactants in said first reactor zone and form said reactionproduct fluid only in said first reactor zone, and the components ofsaid first reactor zone which are selected from the group consisting ofsaid reaction product fluid, unreacted said first reactant, unreactedsaid second reactant and combinations thereof exit only from said firstreactor zone, wherein said porous wall through which said one or moresecond reactants passes into said first reactor zone has a viscositynormalized permeability ranging from about 10⁻⁶ to about 5×10⁻² cm³cp/cm² sec psi.
 27. The process of claim 26 wherein said mixing elementsin said first reactor zone have at least one dimension which is equal tofrom about 1/2 to about 1/100 of the largest dimension of said firstreactor zone wherein said one dimension and said largest dimension aremeasured in the dimension which is perpendicular to the flow of said oneor more first reactants through said first reactor zone.
 28. Anexothermic process for forming a reaction product fluid by reaction ofone or more liquid first reactants with one or more second reactants, atleast one of which is gaseous, which comprises:(a) feeding said one ormore liquid first reactants at a first pressure through a first reactorzone having mixing elements therein; (b) feeding said one or more secondreactant, at least one of which is gaseous at ambient conditions, at asecond pressure higher than said first pressure into a second reactorzone which is separated from said first reactor zone by a porous wallwhich is capable of being penetrated by said one or more secondreactants at multiple sites to produce in said first reactor zone aresulting mixture having components selected from the group consistingof said reaction product fluid, unreacted said first reactant, unreactedsaid second reactant and combinations thereof and (c) maintaining thepressure within said second reaction zone higher than the pressure insaid first reaction zone at corresponding locations of said porous wall,to thereby inhibit any flow back of the components of said first reactorzone which are selected from the group consisting of said reactionproduct fluid, unreacted said first reactant, unreacted second reactantand combinations thereof through said porous wall from said firstreactor zone to said second reactor zone; wherein said one or moresecond reactants pass once through said porous wall to contact said oneor more liquid first reactants in said first reactor zone and form saidreaction product fluid only in said first reactor zone, and thecomponents of said first reactor zone which are selected from the groupconsisting of said reaction product fluid, unreacted said firstreactant, unreacted said second reactant and combinations thereof exitonly from said first reactor zone, wherein said porous wall throughwhich said one or more second reactants passes into said first reactorzone has a viscosity normalized permeability ranging from about 10⁻⁶ toabout 5×10⁻² cm³ cp/cm² sec psi.
 29. The process of claim 28 whereinsaid mixing elements in said first reactor zone have at least onedimension equal to from about 1/2 to about 1/100 of the largestdimension of said first reactor zone normal to the flow of said one ormore liquid first reactants through said first reactor zone.
 30. Theprocess of claim 29 wherein said porous wall comprises one or moreporous tubes which separate said first reactor zone from said secondreactor zone.
 31. An exothermic process for forming a reaction productfluid by reaction of one or more first reactants and one or more secondreactants which comprises:(a) feeding a first reactant at a firstpressure through a first reactor zone containing mixing elements havingat least one dimension which is equal to from about 1/2 to about 1/100of the largest dimension of said first reactor zone wherein said onedimension and said largest dimension are measured in the dimension whichis perpendicular to the flow of said first reactant through said firstreactor zone; (b) feeding a second reactant at a second pressure higherthan said first pressure into a second reactor zone separated from saidfirst reactor zone by a porous wall having multiple openings capable ofbeing penetrated by said second reactant at multiple sites to produce insaid first reactor zone a resulting mixture having components selectedfrom the group consisting of said reaction product fluid, unreacted saidfirst reactant, unreacted said second reactant and combinations thereof;and (c) maintaining the pressure within said second reaction zone higherthan the pressure in said first reaction zone at corresponding locationsof said porous wall, to thereby inhibit any flow of the components ofsaid first reactor zone which are selected from the group consisting ofsaid reaction product fluid, unreacted said first reactant, unreactedsecond reactant and combinations thereof through said porous wall fromsaid first reactor zone to said second reactor zone; whereby said secondreactant passes through said porous wall to contact said first reactantin said first reactor zone and form said reaction product only in saidfirst reactor zone, and the components of said first reactor zone onewhich are selected from the group consisting of said reaction productfluid, unreacted said first reactant, unreacted said second reactant andcombinations thereof exits only from said first reactor zone, whereinsaid porous wall through which said one or more second reactants passesinto said first reactor zone has a viscosity normalized permeabilityranging from about 10⁻⁶ to about 5×10⁻² cm³ cp/cm² sec psi.
 32. Theprocess of claim 31 wherein at least one of said reactants is a liquid.33. A process for forming a reaction product fluid by reaction of afirst liquid reactant with a second liquid reactant, which processcomprises:(a) feeding a first liquid reactant at a first pressure into afirst reactor zone containing particles having at least one dimensionwhich is equal to from about 1/2 to about 1/100 of the largest dimensionof said first reactor zone wherein said one dimension and said largestdimension are measured perpendicular to the flow of said liquid reactantthrough said first reactor zone; (b) feeding a second liquid reactant ata second pressure higher than said first pressure into a second reactorzone separated from said first reactor zone by a porous wall capable ofbeing penetrated by said second liquid reactant at multiple sites toproduce in said first reactor zone a resulting mixture having componentsselected from the group consisting of said reaction product fluid,unreacted said first reactant, unreacted said second reactant andcombinations thereof; and (c) maintaining the pressure within saidsecond reaction zone higher than the pressure in said first reactionzone at corresponding locations of said porous wall, to thereby inhibitany flow through said porous wall from said first reactor zone to saidsecond reactor zone, of the components of said first reactor zone whichare selected from the group consisting of said reaction product fluid,unreacted said first reactant, unreacted second reactant andcombinations thereof; whereby said second liquid reactant passes throughsaid porous wall to contact said first liquid reactant in said firstreactor zone and form said reaction product fluid comprising a liquid, agas, or combinations thereof only in said first reactor zone, and thecomponents of said first reactor zone which are selected from the groupconsisting of said reaction product fluid, unreacted said firstreactant, unreacted said second reactant and combinations thereof exitonly from said first reactor zone, wherein said porous wall throughwhich said one or more second reactants passes into said first reactorzone has a viscosity normalized permeability ranging from about 10⁻⁶ toabout 5×10⁻² cm³ cp/cm² sec psi.
 34. The process of claim 33 whereinsaid porous wall through which said second liquid reactant passes intosaid first reactor zone has a viscosity normalized permeability rangingfrom about 5×10⁻⁶ to about 5×10⁻⁵ cm³ cp/cm sec.
 35. The process ofclaim 34 wherein said porous wall comprises one or more porous tubeswhich separate said first reactor zone from said second reactor zone.36. A process for forming a product by reaction of one or more firstreactants and one or more second reactants which comprises:(a) feedinginto a first reactor zone having mixing elements therein said one ormore first reactants at a first pressure; (b) feeding one or more ofsaid second reactants at a second pressure higher than said firstpressure into a second reactor zone separated from said first reactorzone by a porous wall which is capable of being penetrated by saidsecond reactant at multiple sites to produce in said first reactor zonea resulting mixture having components selected from the group consistingof said reaction product fluid, unreacted said first reactant, unreactedsaid second reactant and combinations thereof; and (c) maintaining thepressure within said second reaction zone at all locations of saidporous wall higher than the pressure in said first reaction zone atcorresponding locations of said porous wall, to thereby inhibit any flowof the components of said first reactor zone which are selected from thegroup consisting of said reaction product fluid, unreacted said firstreactant, unreacted second reactant and combinations thereof throughsaid porous wall from said first reaction zone to said second reactionzone; wherein said one or more second reactants will pass through saidporous wall to contact said one or more first reactants in said firstreactor zone and form said product only in said first reactor zone, andthe components of said first reactor zone which are selected from thegroup consisting of said reaction product fluid, unreacted said firstreactant, unreacted said second reactant and combinations thereof exitonly from said first reactor zone wherein the flow of the first reactantis pulsed flowed at a rate which changes the flow rate from about amaximum flow rate in one direction to zero flow and then to about 20% ofthe maximum rate in the reverse direction and thereafter returns to themaximum flow rate in the original direction, wherein said porous wallthrough which said one or more second reactants passes into said firstreactor zone has a viscosity normalized permeability ranging from about10⁻⁶ to about 5×10⁻² cm³ cp/cm² sec psi.
 37. The process of claim 36wherein the flow changes in a pulsed manner from about the maximum flowdown to about 50% of the maximum flow rate and returns to about themaximum flow rate in the original direction.
 38. The process of claim 36wherein in step (c) the rate of flow of the first reactant is pulsed toabout 80% of the maximum rate flow and then returns to about the maximumflow rate in the original direction.
 39. The process of claim 36 whereinin step (c) the rate of the flow of the first reactant is pulsed down toabout 20% of the maximum rate of flow and then returns to about themaximum flow rate in the original direction.
 40. The process of claim 36wherein the pulsed flow has a flow cycle time of between about 0.1 and1000 seconds.
 41. The process of claim 1 wherein the process comprisesstep (d), (e) and (f);(d) conveying a portion of the reaction productfluid of step (c) to an evaporator; (e) separating volatile reactants orvolatile reaction products wherein the vapor pressure of the volatilereactants or volatile reaction products is about 1 mm of Hg or higher atthe temperature of the reaction in step (c) thereby creating a reactionproduct liquid; and (f) recycling all, a portion or none of the reactionproduct liquid of step (e), which is now depleted of volatile reactants,reaction products or a combination thereof, to the first reactor zone ofstep (a).
 42. The process of claim 15 wherein the process comprises step(d), (e) and (f);(d) conveying a portion of the reaction product fluidof step (c) to an evaporator; (e) separating volatile reactants orvolatile reaction products wherein the vapor pressure of the volatilereactants or volatile reaction products is about 1 mm of Hg or higher atthe temperature of the reaction in step (c) thereby creating a reactionproduct liquid; and (f) recycling all, a portion or none of the reactionproduct liquid of step (e), which is now depleted of volatile reactants,reaction products or a combination thereof, to the first reactor zone ofstep (a).
 43. The process of claim 26 wherein the process comprises step(d), (e) and (f);(d) conveying a portion of the reaction product fluidof step (c) to an evaporator; (e) separating volatile reactants orvolatile reaction products wherein the vapor pressure of the volatilereactants or volatile reaction products is about 1 mm of Hg or higher atthe temperature of the reaction in step (c) thereby creating a reactionproduct liquid; and (f) recycling all, a portion or none of the reactionproduct liquid of step (e), which is now depleted of volatile reactants,reaction products or a combination thereof, to the first reactor zone ofstep (a).
 44. The process of claim 28 wherein the process comprises step(d), (e) and (f);(d) conveying a portion of the reaction product fluidof step (c) to an evaporator; (e) separating volatile reactants orvolatile reaction products wherein the vapor pressure of the volatilereactants or volatile reaction products is about 1 mm of Hg or higher atthe temperature of the reaction in step (c) thereby creating a reactionproduct liquid; and (f) recycling all, a portion, or none of thereaction product liquid of step (e) which is now depleted of volatilereactants, reaction products or a combination thereof, to the firstreactor zone of step (a).
 45. The process of claim 31 wherein theprocess comprises step (d), (e) and (f);(d) conveying a portion of thereaction product of step (c) to an evaporator; (e) separating volatilereactants or volatile reaction products wherein the vapor pressure ofthe volatile reactants or volatile reaction products is about 1 mm of Hgor higher at the temperature of the reaction in step (c) therebycreating a reaction product liquid; and (f) recycling all, a portion ornone of the reaction product liquid of step (e) which is now depleted ofvolatile reactants, reaction products or a combination thereof to thefirst reactor zone of step (a).
 46. The process of claim 33 wherein theprocess comprises step (d), (e) and (f);(d) conveying a portion of thereaction product fluid of step (c) to an evaporator; (e) separatingvolatile reactants or volatile reaction products wherein the vaporpressure of the volatile reactants or volatile reaction products isabout 1 mm of Hg or higher at the temperature of the reaction in step(c) thereby creating a reaction product liquid; and (f) recycling all, aportion or none of the reaction product liquid of step (e), now depletedof volatile reactants, reaction products or a combination thereof, tothe first reactor zone of step (a).